Magnolia biondii

So I'm taking a brief break from my planned adaptation/living planet themed entries to show off a few more photos... I did make it to Longwood's Orchid Show last week, and am hoping for another visit shortly so there's a post on orchids in the works, but in the meantime I have a few photos on Google+ available here if you can't wait...

Magnolia biondii

Anyway, If I haven't mentioned it earlier, Magnolias are probably my favorite genus of tree. In fact, I credit the Bigleaf Magnolia (Magnolia macrophylla) with being the plant that got me interested in horticulture, botany, and eventually Botanic Garden Curation. I'll focus on that one later this summer when it is in bloom, but suffice to say it truly challenged my perceptions of what a tree could be, and furthered my appreciation for botanical biodiversity to the extent where I became passionate about sharing these realizations with others.

Framed by a fruiting holly for reference

As far as I know, this is the first Magnolia to bloom, and with them being a tree already known for early spring flowering that should say something. Seeing Magnolia biondii begin to push out flowers in late February or early March is quite regular, though whether or not it ends up getting away with jumping the gun in this fashion varies from year to year. More often than not, winter is not quite ready to depart yet, and another cold snap causes the tree to abandon  the process.

I'd seen the tree begin to break bud here at UDBG after a string of fifty degree days (which coincided with my first ride down DE Route 9 for the season), but when I saw the temperature was going to hit 60 last week I really began to take note. I've never really seen the flower do much more than break bud during my time living in New England, but given my move a little further down south as well as an unconditionally warm winter, I was in a pretty good position to see this flower fully open.

About the best I could do for a closeup... Tree is about 25' tall so
I couldn't zoom in on anything too close... this is cropped

It's definitely a smaller flower than you'd see on later spring magnolias such as the Star or Saucer Magnolia, and the tree as a whole is certainly less prolific in terms of flowering, though it's hard to say for sure if this is characteristic of the species or if this specimen is just struggling. Regardless, I think the flower itself is still interesting. Though not as showy, it is easily recognizable as that of a magnolia, probably closer to Magnolia cylindrica than anything else I've seen. Most noticeably, the pink coloration towards the base is deep, distinct, and prominent.

Maybe it's just that I've been watching Living Planet and am thinking in terms of adaptations, but I'm now puzzled by the early flowering time of this species. Is there in fact a pollinator which operates at these lower temperatures? Or is this an example of Magnolia biondii behaving differently in terms in cultivation versus the way it does in the wild? Unfortunately I don't have a book to reference at the moment as I left my copy of The World of Magnolias at school for a side project I'm working on, but I'll look into it tomorrow and see if I can come up with a better guess.

I'm not sure how much more these flowers will open, but with the weather forecast claiming 60 again tomorrow, I plan on having my camera with me most of the week. I've even spotted a few buds closer to eye level so this might not be the last we see of this tree this year.

Hopefully within the week I'll have the Orchid entry planned out... it's probably going to be a long one but I'm real happy with the photos so far so I'm thinking it will be a good one.

Fresh Water

Cover art from Wikipedia

I've been rewatching The Living Planet as of late, a classic nature documentary series from David Attenborough (his second actually) which aired in the early to mid 1980s. Though visually it can't quite stack up to some of his more recent work such as Planet Earth, it is interesting to see him taking a more active on-screen role in this series including acts such as narrating the segment on the oceans while in a diving suit, experiencing zero-gravity in a plane during the segment on the skies, and climbing to the top of a canopy tree in the jungle (during which he allegedly left his microphone on, treating his crew to a mix of panic, prayer, and profanity the entire way up).

One thing that really made The Living Planet unique however was that it really focused on the adaptations that various creatures of the earth had developed in order to more successfully survive in their environment. I thought it might be interesting to pick a plant species which would grow in each of these habitats, and cover some of the adaptations or characteristics it displays which allow it to really thrive there.

The first topic covered in the series (at least on the DVD I have, a Christmas Present from my friend Dave a year or two back) is Fresh Water. I actually do have a few photos of freshwater plants which I took upon moving here when I was doing some volunteering at Longwood.

Nymphaea, the Water Lily

Obviously since this plant grows in water instead of upon land, there are a few additional challenges it faces. First off, light does not travel through water as well as air, so it would be difficult for a truly underwater leaf to photosynthesize very effectively. The way the water lily has circumvented this is to ensure that its leaves grow on the surface of the water, able to photosynthesize without losing any of the brightness of the leaf. In fact, in many aquatic plants, the chlorophyll in the leaf tends to be exclusively on the top side, though I'm not sure if this is the case in Nymphaea.

Leaves float (so long as they are alive anyway) due to air pockets within their leaves, which exist due to gas exchange taking place during photosynthesis. It is worth noting how thin and flat this leaf is however, ensuring that water is unlikely to pool up on top of the leaf and cause it to sink.

A Lotus (Nelumbo), at Blithewold

It's not merely the leaves which hold this plant up though. As you can see in the above photo, this plant does have stems connected to these leaves, which in turn connect to roots and anchor it to the bottom of the water body. The shoots tend to be hollow, decreasing their density and encouraging their floating as well.

However, this erroneously sort of portrays the plant as fearing the water. There are obviously a good deal of benefits for the plant resulting from being submerged in water. For one, water retention becomes a non-issue. Land plants have stomates (stomata) in their leaves, essentially pores for gas exchange. They try to keep these closed as much as possible to reduce transpiration. Since aquatic plants don't have to worry about drying out, their stomata tend to be open most of the time.

So, suffice to say, plants can grow just fine in the water, as long as they can keep their leaves out of it.

I actually forget what this is, but note that even though the margins of the leaves are raised, there are still "gabs" through which the water could run off were the leaf to become submerged. I think this plant may have actually had a few other tissues which aided in its floating but can't quite remember... I'll have to check back in the summer.

I'm not sure how regularly I'm going to do these (I'd like to do some more Tree ID over the next few weeks), but the next one will probably be on the Jungle, focusing on how epiphytic orchids use their roots (and probably a bit more on orchids as well as I want to get down to the Longwood Orchid show and take some pictures).

the birch

I was planning on writing a bit on Nandina domestica (Heavenly Bamboo), but the shots I took quickly on Sunday aren't quite up to the quality I'm holding myself to so I think I need to spend a little more time on that first.

However, did take some other photos over the weekend while preparing for a lab on native trees I'm teaching this semester. Though I took these more to emphasize easy identification characteristics instead of the ornamental appeal of the plant, I still think it's a good excuse to talk a little bit about one group of our native trees: the birches.

Paper Birch (Betula papyrifera)
Note the cluster of three male catkins on the end of the branch

The Paper Birch is probably the first one that comes to mind when I think of a birch tree. It's actually one of the first trees I remember being interested in as a kid. Growing up on the Vineyard I was used to seeing Black Oaks, White Oaks, Pitch Pine, Sassafras, the occasional Red Maple, and that was about it. I saw one while up in Maine one summer, and remembered being confused over how different it was than any tree I'd seen before, with the thin, papery white bark smooth and cool to the touch. Maybe still as a result of this, like many birches, I'd probably claim the bark is the most significant feature of this tree.

So if that's the case then why did I relegate it to the background in the above photo? I didn't even widen the depth of field enough to bring it remotely into focus. Well, I was trying to highlight a group of catkins (essentially clusters of petal-less flowers), as they serve as a good characteristic to distinguish it from a similar species, the Gray Birch.

Grey Birch (Betula populifolia)
With a solitary male catkin

The name Grey Birch typically refers to the bark of this species, which is evident in the photo above mostly because of the lighting. If you see these plants out in the woods together though, sometimes both the Paper Birch and Grey Birch will have sort of an off-white color to the bark making them hard to tell apart. However, on this tree the male catkins tend to be solitary, instead of clustered as in the Paper Birch.

Yellow Birch (Betula alleghaniensis)

You might also see female catkins on birches, which are a bit stouter, and generally not on the tips of the branches. If you're in doubt over whether you have a male or female catkin, try rubbing it back and forth with your fingers. The female catkins will break apart rather easily while the males won't. And of course, there are male and female catkins on this tree as there are independent male and female flowers.

Now for the next three I actually do have the bark in full focus. First up is the Yellow Birch, or Betula alleghaniensis. The botanical name of this changed at some point, so you may see Betula lutea in reference to this species. The name lutea refers to the yellow, or golden lustre to the bark of this species. Now "yellow" probably isn't the first thing that comes to mind when looking at this tree, but once you think to look for it, there is a bit of a dark golden tinge to the bark, interrupted by the pattern of thick, obvious lenticels - pores of the tree used for gas exchange.

Were you to actually scratch the thin layer of bark open, you'd pick up on a familiar somewhat sweet odor: Oil of Wintergreen. The odor will not be quite so strong however as it would be for the Sweet Birch (Betula lenta)

Sweet Birch (Betula lenta)

The Sweet Birch is a similar looking tree to that of the Yellow Birch, but lacks that golden coloration. The Oil of Wintergreen it produces serves as a flavoring agent in Birch Beer. I've never been a huge soda aficionado, so I had actually never tried this (well, or at least don't remember it) until a few years ago. It was OK. I had the Polar brand (Worcester's finest), so I'm not sure if that was the best direction to go. I'd say this tree is a little less ornamental than the other one's I've listed here, but has actually become rather important in New England ecologically speaking as it's starting to take over the forests traditionally inhabited by Eastern Hemlock, which are dying off due to the threat of Hemlock Wooly Adelgid.

River Birch (Betula nigra)

Finally, we have the River Birch, which can be readily identified by the reddish-tan colored bark, peeling off the plant with enough of a fervor to leave bare spots on the trunk. I'd say this is one of the more common birches cultivated in the landscape. For my friends in Boston, there's an aspiring grove of these about halfway down the Greenway (Somewhere between the Aquarium and the Intercontinental). They do put on a nice show in the fall when the leaves turn a brilliant yellow. I did find those trees a bit difficult to work with as I seemed to be constantly having to prune the lower branches, as well as water the trees heavily in the dead of summer, also proving difficult as the trees were planted on raised grass mounds which the water tended to roll off of. As the common name suggests, River Birches do like their water, and seeing the fall color show in mid-July can be a bit disconcerting.

Though I didn't explicit mention it throughout the article, I hope you're gaining a bit of an appreciation for some of the sight recognition tricks someone like me would use to quickly identify a birch tree while in the field. If I see a tree that I can identify as probably being a birch, to figure out which birch is a matter of asking myself a few questions: Is the bark peeling heavily? Do the twigs have a sweet soda-like smell when scratched? If so does the bark look golden? And if the bark is white, thin, and papery, how many male catkins does it display?

Next time you think you see a birch out in the woods try asking yourself the above and see what you come up with. Especially since you can't use the LeafSnap app since it's winter (though at 50 degrees again today I'm still not convinced).

and finally, the indehiscent fruits

Line drawing of Common Buckwheat from
wikipedia. Note the fruit in the lower right.